1. Technical Field
The present invention relates to an image forming apparatus provided with a plurality of cooling fans and the like such as a copier, a printer, and a Multi Function Peripherals (MFP) of a multi-function digital complex apparatus, and to a method for driving and controlling the fans in the apparatus.
2. Description of the Related Art
The following description sets forth the inventor's knowledge of related art and problems therein and should not be construed as an admission of knowledge in the prior art.
The image forming apparatus described above is usually provided with a plurality of fans such as a cooling fan for preventing the temperatures of an electronic board, an electric motor, or the interior of the apparatus from being higher than a predetermined temperature during an operation such as a printing operation, a fan for sucking ozone, dust, or the like, and a fan for sucking paper.
These fans cause noises when they are activated, so that it is required for the fans not only to have performances intrinsic to the fans such as cooling performance and sucking performance but also to reduce the noises of all the fans in recent years.
Thus, in Japanese Patent Application Laid-Open No. 2009-58587 is proposed an image forming apparatus having a silent mode in which noises are reduced as compared with an ordinary mode by reducing the noises of the fans leaking from the openings of the apparatus.
Further, in Japanese Patent Application Laid-Open No. 2000-250381 is proposed an image forming apparatus that controls a plurality of cooling fans according to an outside air temperature or on the basis of a temperature detection result to thereby reduce the noises.
However, the image forming apparatus in the prior art including the image forming apparatuses described in Japanese Patent Application Laid-Open No. 2009-58587 and Japanese Patent Application Laid-Open No. 2000-250381 presents such problems that the image forming apparatus is not sufficient in terms of suppressing a noise level and that the noise level of the fans is rapidly changed in some cases depending on the use conditions of the apparatus to be offensive to user's ears.
The description herein of advantages and disadvantages of various features, embodiments, methods, and apparatus disclosed in other publications is in no way intended to limit the present invention. Indeed, certain features of the invention may be capable of overcoming certain disadvantages, while still retaining some or all of the features, embodiments, methods, and apparatus disclosed therein.